diff --git a/Assets/UniGLTF/Runtime/UniJSON/ListTreeNode/ListTreeNodeObjectExtensions.cs b/Assets/UniGLTF/Runtime/UniJSON/ListTreeNode/ListTreeNodeObjectExtensions.cs
index 5f884988c..8cf8078fe 100644
--- a/Assets/UniGLTF/Runtime/UniJSON/ListTreeNode/ListTreeNodeObjectExtensions.cs
+++ b/Assets/UniGLTF/Runtime/UniJSON/ListTreeNode/ListTreeNodeObjectExtensions.cs
@@ -52,7 +52,7 @@ namespace UniJSON
                     return kv.Value;
                 }
             }
-            throw new KeyNotFoundException();
+            throw new KeyNotFoundException(key.ToString());
         }
 
         public static bool ContainsKey(this JsonNode self, Utf8String key)
diff --git a/Assets/VRM10/Runtime/Migration/MigrationVector3.cs b/Assets/VRM10/Runtime/Migration/MigrationVector3.cs
index 385461de4..1587e300b 100644
--- a/Assets/VRM10/Runtime/Migration/MigrationVector3.cs
+++ b/Assets/VRM10/Runtime/Migration/MigrationVector3.cs
@@ -21,5 +21,14 @@ namespace UniVRM10
                 vrm0["z"].GetSingle(),
             };
         }
+
+        public static float[] Migrate(JsonNode parent, string key)
+        {
+            if (!parent.ContainsKey(key))
+            {
+                return new float[] { 0, 0, 0 };
+            }
+            return Migrate(parent[key]);
+        }
     }
 }
diff --git a/Assets/VRM10/Runtime/Migration/MigrationVrmFirstPersonAndLookAt.cs b/Assets/VRM10/Runtime/Migration/MigrationVrmFirstPersonAndLookAt.cs
index adecb3871..1313adf21 100644
--- a/Assets/VRM10/Runtime/Migration/MigrationVrmFirstPersonAndLookAt.cs
+++ b/Assets/VRM10/Runtime/Migration/MigrationVrmFirstPersonAndLookAt.cs
@@ -1,8 +1,10 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using UniGLTF;
 using UniGLTF.Extensions.VRMC_vrm;
 using UniJSON;
+using UnityEngine;
 
 namespace UniVRM10
 {
@@ -39,14 +41,15 @@ namespace UniVRM10
         {
             // VRM1
             // firstPerson に同居していた LookAt は独立します
-            var lookAt = new LookAt
+            LookAt lookAt = default;
+            lookAt = new LookAt
             {
                 RangeMapHorizontalInner = MigrateLookAtRangeMap(vrm0["lookAtHorizontalInner"]),
                 RangeMapHorizontalOuter = MigrateLookAtRangeMap(vrm0["lookAtHorizontalOuter"]),
                 RangeMapVerticalDown = MigrateLookAtRangeMap(vrm0["lookAtVerticalDown"]),
                 RangeMapVerticalUp = MigrateLookAtRangeMap(vrm0["lookAtVerticalUp"]),
                 Type = MigrateLookAtType(vrm0["lookAtTypeName"]),
-                OffsetFromHeadBone = MigrateVector3.Migrate(vrm0["firstPersonBoneOffset"]),
+                OffsetFromHeadBone = MigrateVector3.Migrate(vrm0, "firstPersonBoneOffset"),
             };
 
             var firstPerson = new FirstPerson
diff --git a/Assets/VRM10/Runtime/Migration/MigrationVrmMeta.cs b/Assets/VRM10/Runtime/Migration/MigrationVrmMeta.cs
index 5756bc275..3b87c2b9b 100644
--- a/Assets/VRM10/Runtime/Migration/MigrationVrmMeta.cs
+++ b/Assets/VRM10/Runtime/Migration/MigrationVrmMeta.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using UniJSON;
+using UnityEngine;
 
 namespace UniVRM10
 {
@@ -152,7 +153,8 @@ namespace UniVRM10
                         break;
 
                     default:
-                        throw new NotImplementedException(key);
+                        Debug.LogWarning($"[meta migration] unknown key: {key}");
+                        break;
                 } // switch
             } // foreach